Such assembly comprises a gas bag accommodated by a housing, which for the protection of a driver is inflatable by means of a gas generator, and a shiftably mounted carrier for accommodating the housing, which can be positioned at the steering wheel in a rest position and at least one deflected position. The steering wheel assembly in addition comprises at least one fastening device, by means of which the carrier is to be shiftably fixed at a steering wheel skeleton of the steering wheel. There is a spring associated to the fastening device, which biases the carrier into the rest position. Furthermore, the fastening device includes a guiding portion along which the carrier is shiftable into the deflected position against the force of the spring, namely along a main shifting direction along which the distance between the carrier and the steering wheel skeleton is reduced. Between the carrier and the guiding portion a clearance exists in a direction transverse to the main shifting direction, which provides for a free movability of the carrier along the main shifting direction.
With such an assembly it is possible to inflate the gas bag between the driver and the steering wheel by means of the gas generator for the protection of the driver of a motor vehicle in the case of an accident.
The shiftability of such steering wheel assembly together with the associated carrier in a direction, for example in direction of the longitudinal axis of the steering column, can serve to use a cover with which the steering wheel assembly is covered as actuating surface for a horn of the motor vehicle. The same is triggered when the cover is depressed and hence the assembly is shifted along the longitudinal axis of the steering column.
In order not to impede the shiftability of the steering wheel assembly, a gap is left between the edge of the cover of the assembly and an inner trim of a steering wheel pot into which the assembly is inserted. This gap should be as narrow and as uniform as possible. To achieve this, fastening devices are known, which in a non-mounted condition are movable with respect to the carrier of the steering wheel assembly at least along a degree of freedom transversely to the longitudinal axis of the steering column. During the assembly, the steering wheel assembly thereby can be positioned in the steering wheel such that manufacturing tolerances and mounting tolerances of the steering wheel assembly and the steering wheel can be compensated up to a certain extent. For this purpose, for example, a fastening device with cylindrical outer shape is used.
A steering wheel assembly as mentioned above is known from DE 10 2006 005 642 A1.
One difficulty when mounting such steering wheel assembly consists in designing the gap between the edge of the cover and the inner trim of the steering wheel pot, into which the steering wheel assembly is inserted, as narrow and uniform as possible, without jamming or the generation of noise occurring when the steering wheel assembly, or the carrier, is shifted into a deflected position and likewise from a deflected position into the rest position.